JPH05134767A - Pressure control device - Google Patents

Abstract

PURPOSE:To realize a pressure control device capable of quickening a response and properly controlling in accordance with pressure state. CONSTITUTION:The error between detection data D2 of a pressure detector provided in the vicinity of a piping nozzle and a preliminarily set setting value Ds is amplified by a differential amplifier 5. The amplified value is integrated by an integration circuit 6 and controls a pressure regulator, and a time constant switching circuit 10 controls an analog switch 8 based on the output value of the differential amplifier circuit 5 and switches the time constant of the integration circuit 6. Therefore, a control response can be changed in accordance with the state of the detection data D2 and an optimum control always becomes possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure control device suitable for controlling the blowout gas pressure of a laser processing machine or the like.

[0002]

2. Description of the Related Art A pressure control device for controlling a pressure regulator for adjusting the pressure to a constant level based on the detection result of a pressure detector for detecting the pressure has been conventionally known. However, the above-mentioned conventional one has a slow response,
There was a drawback that pressure pulsation occurred when the response was quick. Further, there is also a drawback that it takes a long time to rise, that is, to start the operation because of the electric charge stored in the capacitor of the integrating circuit.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a pressure control device which has a fast response and is always capable of accurate control. To provide.

[0004]

In the pressure control device of the present invention, a pressure detector provided near the nozzle, a pressure regulator for adjusting the pressure to a constant value, and detection data of the pressure detector are preset. In a pressure control device for controlling the pressure regulator based on pressure data, the pressure control device includes a differential amplifier that amplifies an error between the two data, and an integration circuit that integrates outputs of the differential amplifier.
It comprises a time constant switching means for switching the integration time constant of the integration circuit based on the output value of the differential amplifier and a reset means for putting the integration circuit in a reset state.

Further, the pressure regulator is provided with a pressure sensor for detecting the pressure, the differential value of the pressure sensor is added to the detection data of the pressure detector, and the added value is led to a differential amplifier. Is.

An addition circuit for adding preset pressure data and the output value of the integration circuit is provided.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a pressure control device according to the present invention.
It will be described with reference to FIG.

FIG. 1 is an overall block diagram of a gas pressure control system of a laser processing machine.

In the figure, 1 is a gas pipe, 2 is a pressure detector provided near the nozzle 1a of the pipe 1 for detecting the pressure of the nozzle 1a, 3 is a pressure regulator for adjusting the gas pressure of the pipe 1, and 4 is a pressure detector. 2 is a control circuit for controlling the pressure regulator 3 based on the detection data D2 of No. 2 and the preset value Ds.

FIG. 2 is a block diagram of the control circuit 4, and FIG. 3 is a concrete circuit diagram of the control circuit 4.

In the figure, 5 is detection data D2 of the pressure detector 2.
And a differential amplifier for increasing an error between a preset setting value Ds and 6; an integrating circuit 6 for integrating the output value of the differential amplifier 5;
Is a buffer circuit for controlling the pressure regulator 3 when the integrated value of the integrator circuit 6 reaches a constant level, 8 is an analog switch for switching the integral time constant of the integrator circuit 6, and 9 is a set value Ds of 0, that is, a pressure. When the control is not performed, a reset circuit for controlling the analog switch to bring the integrating circuit 6 into the reset state in order to prevent erroneous output due to accumulation of charges in the capacitor forming the integrating circuit 6 is a differential amplifier 5 Is a time constant switching circuit that switches the integration time constant of the integration circuit 6 via the analog switch 8 in order to speed up or slow down the control response based on the output value of.

Next, the switching of the integration time constant of the integration circuit 6 and the reset circuit will be described based on the specific circuit diagram of FIG.

The resistors R1 and R2 and the capacitor C1 are elements that determine the time constant of the integrating circuit 6.

Now, when the set value Ds is not set,
In order to prevent erroneous output due to the electric charge of the capacitor C1, a resistor R3 shunts both ends of the capacitor C1 so that the electric charge of the capacitor C1 is quickly discharged.

Whether or not the set value Ds is 0 is detected by the reset circuit 9 including the comparator 9a, and the set value Ds is set.
When it is detected that 0 is 0, b and c are connected via the analog switch 8.

Normally, the resistors R1 and R2 are connected in parallel by the analog switch 8 to reduce the time constant and speed up the control response, but the output value of the differential amplifier circuit 5 is within a certain range. If the time constant switching circuit 10 composed of the comparators 10a and 10b detects this state, it connects between a and b via the analog switch 8 to delay the control response.

Therefore, in this circuit, since the integration time constant of the integrating circuit 6 is switched according to the detection result of the detection data D2, the state of the control response can be changed, and the state is always adapted. The best control can be performed.

4 and 5 show another embodiment of the present invention, FIG. 4 is a block diagram, and FIG. 5 is a circuit diagram showing a concrete circuit.

In the figure, 11 is an adder circuit provided to enhance the control response of the pressure regulator 3. That is, the adder circuit 11 is configured to add the integrated value of the integrator circuit 6 and the set value Ds, so that the set value Ds is directly guided to the pressure regulator 3 via the adder circuit 11 at the time of rising. For this reason, it rises at a high speed and then is controlled as shown in FIG.

Some pressure regulators have a built-in pressure sensor to enable high-speed response.

Built-in pressure sensor (shown at 3a in FIG. 1)
In order to speed up the response because the pressure data D3a can be obtained first by the pressure detector 2, the differential circuit 12 differentiates the pressure data D3a, and then the detected data of the pressure detector 2 is differentiated into the differentiated value. D2 is added by the adder 13 and this value is guided to the differential amplifier 5 to reduce the overshoot and make the control more appropriate.

[0022]

According to the pressure control device of the present invention,
Since it is configured as described above, it is possible to speed up the response and, moreover, to perform appropriate control according to the pressure state. Therefore, the pressure has no pulsation. In particular, in the laser processing machine, the gas pressure is determined by the thickness of the metal plate to be cut, and the gas pressure can be finely controlled from low pressure to high pressure.

[Brief description of drawings]

FIG. 1 is a block diagram of a gas pressure control system of a laser processing machine showing an embodiment of a pressure control device of the present invention.

FIG. 2 is a block diagram of a control circuit in FIG.

FIG. 3 is a circuit diagram in FIG.

FIG. 4 is a block diagram showing another embodiment of the present invention.

FIG. 5 is a circuit diagram in FIG.

[Explanation of symbols]

 1 gas piping 2 pressure detector 3 pressure regulator 4 control circuit 5 differential amplifier 6 integration circuit 7 buffer 8 analog switch 9 integration reset 10 time constant switching circuit Ds set value D2 detection data

Claims (3)

[Claims] 1. A pressure detector provided near a nozzle, a pressure regulator for adjusting the pressure to a constant value, and a pressure for controlling the pressure regulator based on the detection data of the pressure detector and preset pressure data. In the control device, in the pressure control device, the pressure control device includes a differential amplifier that amplifies an error between the two data, an integrating circuit that integrates outputs of the differential amplifier, and an output of the differential amplifier. A pressure control device comprising: a time constant switching means for switching an integration time constant of the integration circuit based on a value; and a reset means for causing the integration circuit to be in a reset state. 2. A pressure regulator for detecting pressure is provided in the pressure regulator, and the differential of this pressure sensor is added to the detection data of the pressure detector, and the added value is led to a differential amplifier. The pressure control device according to claim 1, wherein: 3. The pressure control device according to claim 1, further comprising an addition circuit for adding preset pressure data and an output value of the integration circuit.